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Subject:
From:
Joe Russeau <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Joe Russeau <[log in to unmask]>
Date:
Wed, 30 Apr 2008 14:09:02 -0400
Content-Type:
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Hi Chris,

Perhaps, I'm reading your post incorrectly, but it comes across (at least to 
me) that you are wanting to know what changes you should make to your 
process in order to get the best result from the cleaner.  Really, you 
should be focused on whether the cleaner removes the soils left by your 
process. If it doesn't, then perhaps it's not the right cleaner.

As for methods, you indicate three techniques that will be of value for 
evaluating the cleaner and any residual process residues / chemical 
interactions.  Here are a few quick suggestions (take em for what they are 
worth):

1) Select a test vehicle for SIR and/or ECM that closely matches your 
assembly technology.  A functional assembly will not work for this type of 
testing.  The IPC-B-52 would be one good choice.  It also has breakaway 
coupons for IC testing.  Two drawbacks; 1) it is a little expensive and 2) 
it does not have an extensive data history.  Doug Pauls designed the B-52 
and will likely comment.  The IC portion of your testing could also be done 
on functional product.

2)  Process the boards as you would normally do.  The cleaner needs to prove 
that it can remove your assembly and fabrication residues and not leave 
harmful materials behind. If you have several processes and materials, 
choose one that is representative of most of your product or one that 
represents a worse-case scenario.

3) If you are doing any conformal coating, then it may be advisable to also 
to include thermal shock, just to verify that adhesion and coating 
properties do not change as a result of this new cleaner.

4) Visual inspections should be done.

5)  I would also suggest doing a comparative study to your current material. 
This will allow you to evaluate how the new stuff compares with the stuff 
your replacing.

6) If you use ROSE testing to monitor the process on a regular basis, it 
would be a very good idea to include this as part of your test matrix.  I 
would suggest processing enough samples to do ROSE testing (use your own 
tester), along with the IC, SIR and or ECM.  This will help you establish a 
baseline for your ROSE tester while qualifying the new cleaner at the same 
time.

7) Always, always, always, send samples of the unprocessed boards and 
components to act as controls.  If I had a nickel for every test I've seen 
where the customer doesn't include the unprocessed boards, I'm sure I could 
almost pay off my diet Mt. Dew tab to Doug.

Anyway, just a few thoughts to help get the ball rolling.  I'm sure others 
will comment and make suggestions.

Best Regards,

Joe Russeau
Precision Analytical Laboratory, Inc.





----- Original Message ----- 
From: "Chris Schaefer" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, April 30, 2008 12:58 PM
Subject: [TN] Hand Cleaning Chemistry Qualification


TechTeam,

We are in the very beginning stages of starting a conversion from one hand
cleaning solvent to another more effective one. I am curious what makes the
most sense in terms of methods to use to qualify as well as what is the 
likely
norm from the industry? We are required to perform SIR or ECM, and IC 
testing
by various customers prior to any changes which I think is a good thing, but
what would be the application process of flux, soldering, and finally 
cleaning?
As well as the actual soldering and cleaning process. With the various
geometries, spacing, ground planes, thermal requirements, materials, time,
etc... How would best capture the effectiveness of the new solvent? We are
currently using an RMA 15% solid flux, hand soldering with 600-700dgree tips
on multi-layer product from FR4 to teflon. I hope I didn't open a huge 
can-o-
worms.

Thanks all and have a great day!

Chris

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